Dr. Jannsen and his father Hans were dutch eye glass makers who invented the microscope
Robert Hooke was an English philosopher. He discovered cells by looking in a microscope and observed that the cells looked similar to to rooms.
Anton Van Leeuwenhoek was a Dutch tradesman and scientist. He looked at a pond with a microscope he made lenses for.
Matthias Schlelden was a German botanist composed that all plant tissues are composed of cells
In 1838 Matthias Schleiden had stated that plant tissues were composed of cells. Schwann demonstrated the same fact for animal tissues, and in 1839 concluded that all tissues are made up of cells: this laid the foundations for the cell theory.
Virchow is credited with several very important discoveries. His most widely known scientific contribution is his cell theory, which built on the work of Theodor Schwann.